Generates a versions.properties files to be used by gradle in android project to set versions on android apps

build.gradle.kts

import java.util.Properties


val versionFile = File("versions.properties")
val versions = Properties().apply {
    if (versionFile.exists()) {
        FileInputStream(versionFile).use {
            load(it)
        }
    }
}


android {
  defaultConfig {
        versionName = versions.getProperty("V_VERSION", "1.0.0")
        versionCode = versions.getProperty("V_VERSION_CODE", "1000000").toInt()
  }
}

generate_versions.sh

#!/bin/bash

# Generates a versions.properties files to be used by gradle in android project to set versions on android apps

# Overwrite versions.properties at the beginning
: > versions.properties

# Define the prefixes
prefixes=("v" "a")

# Get the latest commit hash
hash=$(git rev-parse --short HEAD)

# Check if the working directory is dirty
git diff --quiet || dirty=true
dirty=${dirty:-false}

# Loop over the prefixes
for prefix in "${prefixes[@]}"; do

    # Get the latest git tag from current branch that matches the current prefix
    tag=$(git describe --tags --match "${prefix}[0-9]*" --abbrev=0)

    # Trim the prefix from the start of the tag name
    version="${tag:1}"

    # Split the version into major, minor, and patch parts
    IFS='.' read -r -a version_parts <<< "$version"
    major="${version_parts[0]}"
    minor="${version_parts[1]}"
    patch="${version_parts[2]}"

    # Calculate the version code using arithmetic expansion
    version_code=$((major * 10000 + minor * 100 + patch))

    # Get the number of commits since the tag
    commit_count=$(git rev-list --count "${tag}"..HEAD)

    # Create the debug version string and append -dirty if necessary
    debug_version="${version}-${commit_count}-g${hash}"
    [[ $dirty == true ]] && debug_version+="-dirty"

    # Convert prefix to uppercase for property names
    prefix_upper="${prefix^^}"

    # Print the result
    printf "%s_VERSION=%s\n" "$prefix_upper" "$version"
    printf "%s_DEBUG_VERSION=%s\n" "$prefix_upper" "$debug_version"
    printf "%s_VERSION_CODE=%d\n" "$prefix_upper" "$version_code"

    # Write to versions.properties
    {
        printf "%s_VERSION=%s\n" "$prefix_upper" "$version"
        printf "%s_VERSION_CODE=%d\n" "$prefix_upper" "$version_code"
        printf "%s_DEBUG_VERSION=%s\n" "$prefix_upper" "$debug_version"
    } >> versions.properties

done

# Print more result
printf "HASH=%s\n" "$hash"
printf "DIRTY=%s\n" "$dirty"

# Write the hash to versions.properties after the loop
printf "HASH=%s\n" "$hash" >> versions.properties
printf "DIRTY=%s\n" "$dirty" >> versions.properties